Pathogens isolated from sputum specimens and antimicrobial resistance of pathogens in recent 5 years

Abstract:

ObjectiveTo understand the distribution and antimicrobial resistance of pathogens from sputum specimens of patients with respiratory tract infection in a hospital in recent 5 years, so as to provide basis for infection control and rational use of antimicrobial agents. MethodsBacteria were isolated with routine method, and  were identified  by VITEK 2 and Phoenix100 automated bacterial identification system, antimicrobial susceptibility testing was performed by KirbyBauer  disk diffusion method according to the Clinical and Laboratory Standards Institute standards. ResultsA total of 1 829 pathogenic bacterial strains were isolated from patients in respiratory department between 2009 and 2013, of which gramnegative bacilli and grampositive cocci accounted for 78.84% (n=1 442) and 21.16% (n=387) respectively. The major gramnegative bacilli were Acinetobacter baumannii(A. baumannii 21.76%), Pseudomonas aeruginosa(P. aeruginosa 18.70%), Klebsiella pneumoniae (K. pneumoniae 11.70%) and Escherichia coli(E. coli 7.16%); the major grampositive cocci were Staphylococcus aureus (S. aureus 11.76%) and Enterococcus faecium (E. faecium 4.70%). The average detection rate of extendedspectrum βlactamase (ESBL)producing E. coli and K. pneumoniae was  61.83% and 34.45% respectively. The resistant rates of A. baumannii to amikacin,imipenem and meropenem were all  ＞70%;  the resistant rate of P. aeruginosa to cefepime and  ceftazidime was 22.22% and 51.46% respectively, the resistant rate to imipenem and meropenem was 49.71% and 49.42% respectively.Linezolidresistant S. aureus  strains were found, the resistant rate  of S. aureus to nitrofurantoin was ＜6.0%, the average detection rate of methicillinresistant S. aureus (MRSA) was 88.37%;  the resistant rates of Enterococcus spp. to linezolid and teicoplanin were both 4.35%, the resistant rate to vancomycin was 8.70%. ConclusionThe main pathogens  causing  respiratory tract infection are A.baumannii, P. aeruginosa, K. pneumoniae, E. coli and S. aureus，which have high and multiple resistance to antimicrobial agents.